GitHub plugin authentication fails - browser window not opening

[mappadurai]

Description

When attempting to authenticate the GitHub plugin (Plugin:github:github MCP Server) via /plugin, the browser window does not open and authentication fails.

Error Message

Error: Incompatible auth server: does not support dynamic client registration

Plugin Details

• Plugin: Plugin:github:github MCP Server
• Status: Failed
• Auth: Not authenticated
• URL: https://api.githubcopilot.com/mcp/
• Config location: Dynamically configured

Steps to Reproduce

1. Run /plugin in Claude Code CLI
2. Select GitHub plugin
3. Select "Authenticate"
4. Expected: Browser window opens for OAuth authentication
5. Actual: Error shown, browser never opens

Environment

• OS: macOS (Darwin 25.3.0)
• Claude Code Model: Claude Opus 4.6 (1M context)

Screenshots

The plugin status screen shows the error:

Plugin:github:github MCP Server

Status: ✗ failed
Auth: ✗ not authenticated
URL: https://api.githubcopilot.com/mcp/
Config location: Dynamically configured

Error: Incompatible auth server: does not support dynamic client registration

> 1. Authenticate
  2. Reconnect
  3. Disable

[github-actions]

Found 2 possible duplicate issues:

1. Claude Code cannot connect to GitHub's remote MCP server using OAuth authentication #3433
2. [BUG] Claude Code does not work with MCP servers that does not implement Dynamic Client Registration #3273

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
• To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

[github-actions]

This issue has been automatically closed as a duplicate of #3433.

If this is incorrect, please re-open this issue or create a new one.

🤖 Generated with Claude Code

[github-actions]

This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.